The invention relates to a device for reading information stored on an information plate and/or writing information on an information plate, comprising a stacking unit for the storage of at least two information plates in storage compartments.
Such a device is known, for example, from the document JP 8087811A. Such devices are usually called changer devices. The term information plates is understood to refer to disc-shaped information carriers, for example CDs, CD-ROMs, and DVDs.
The information plates are stacked one above the other in individual pigeonholes. It is necessary for a reliable operation of the changer device that the control of the device should receive information as to which pigeonholes contain an information plate.
Optical sensors are provided in the known device inside the stacking unit for the detection of the information plates, which sensors form a photoelectric barrier.
Such optical sensors tend to become unreliable in the case of pollution. In addition, the sensor function is dependent on the optical reflection or transparency properties of the information plates.
It is an object of the invention to provide an alternative device of the kind mentioned in the opening paragraph which renders possible a reliable, failure-proof detection of the information plates inside the stacking unit.
According to the invention, this object is achieved in that the stacking unit comprises an electromechanical switching unit for detection of the information plates, and in that the switching unit can be operated by the plate edges of the information plates.
Such an electromechanical switching unit operates very reliably, shows no tendency to fail in the case of pollution, and its function is independent of the optical reflection and transparency properties of the information plates.
When an information plate is being transported inside the stacking unit, the electromechanical switching unit is operated by the edge of the respective passing information plate, whereby an electrical signal can be obtained from which the occupation of the individual storage compartments in the stacking unit can be concluded.
The inlet slopes in the embodiment of the invention as claimed in claim 2 render it possible to actuate the switching unit with a very small force.
The dimensioning of the slopes in accordance with claim 3 renders possible a very compact construction of the stacking unit.
The advantageous embodiment of the invention as defined in claim 4 renders it possible to utilize standard components, for example standard contact switches, for the switching unit. This is particularly favorable as regards cost price.
In the advantageous embodiment of the invention in accordance with claim 5, the switching unit may at the same time also be utilized for ascertaining whether the information plate has fully entered the storage compartment during the process of filling the storage compartment, which is in the transitional position. Once it has fully entered the storage compartment, the information plate presses against the switching unit, from which a stop signal can be derived for switching off the transport mechanism. The switch accordingly not only has the function of detecting the occupation of the storage compartment but also a further detection function. This dual function of the switching unit implies that an additional switch can be dispensed with.